Feeding device for films in cinematographic apparatus



J. LAAGER Aug. 24, 1937.

FEEDING DEVICE FOR FILMS IN CINEMATOGRAPHIC APPARATUS Filed May 12, 19362 Sheets-Sheet l J. LAAGER Aug. 24, 1937.

FEEDING DEVICE FOR FILMS IN CINEMATOGRAPHIG APPARATUS Filed May 12, 19362 Sheets-'Shet 2 Patented Aug. 24, 1937 UNITED STATES PATENT OFFIEE JeanLaager, Pery-Reuchenette, Switzerland Application May 12, 1936, SerialNo. 79,347 In Switzerland May 23, 1935 1 Claim.

The present invention relates to an intermittent feeding device forfilms in cinematographic apparatus. t comprises a sprocket feed drumcombined with means imparting to this drum not only a continuousrotarymovement but also a vertical oscillating movement having a quickdownwards stroke which effects the changing of the picture and a slowerupwards stroke which neutralizes the eifect of rotation of the drum onthe film and causes the picture to remain stationary before theprojecting aperture.

The usual feeding system of films by means of sprockets though affordinga steady projection is very injurious for the film. The introducing of asprocket into a hole, the rough and sudden pull upon the film and allthis working solely on the edge of the hole cause a rapid wearespecially in the ultra modern apparatus now on the market which areusing a speaking film of 16 millimeters 0 having only one row of holesand a feeding time of the picture of and even A; of a picture cyclerevolution. All these facts cause a rapid wear which must the more betaken into account as the speaking films are rather expensive.

The reason for introducing a feeding time of the picture of only A; ofthe picture cycle was i to lessen the flicker by using three bladeshutters.

Though the maltese cross gives better results for films having a widthof millimeters and 30 four perforations for each picture it cannot beeasily used for narrower films having but one perforation per picture.

In the annexed drawings one working form is shown of the invention, asan example.

Figs. 1 to 3 are views of the mechanism, Fig. 1 is a side elevationperpendicular to the optical axis, Fig. 2 an elevation parallel to thisaxis and Fig. 3 a plan view.

Fig. 4 a perspective view of the feed arrangement of the film and Figs.5 to 7 show three different positions of the feeding sprocket.

The device shown in the drawings comprises a driving shaft I which isparallel to the optical axis of the cinematograph and is driven by afriction gear 3 from the motor shaft 2. Shaft I carries a three bladedshutter 4, a grooved cam disk 5 and a worm 6, the portion carrying thecam and the worm being enclosed in a casing I which is cast in one piecewith a standard 8 of the frame and accommodates. bearings of shaft I. Ona pivot pin I2 fast to the casing is pivotally held an arm I3 and isfitted a sleeve I 0 integral with a pinion I5 and journaled to thecasing I on the outside of which it carries a sprocket pinion II, for achain drive. Besides sleeve I ii carries next to pinion I5 a worm wheel9 meshing with the worm 6. The rocking arm I3 is guided at its end inthe groove of said cam disk by means of a friction roller l6 and carriesat its middle portion a shaft 3I upon which is fast a spur wheel I4meshing with pinion I5 of the sleeve and a sprocket I8 whereof one halfside is intended for the take-in film and the other half side for thepay-out film. This sprocket is carried by a portion of shaft 3! extendedto the outside of the standard 8. Likewise on the outside of thestandard is held by a bracket the pivot pin of two pressure rollers 22,24 cooperating with the sprocket and arranged in such a way that thepay-out film enlaces the sprocket on the whole half of its circumferencethus bringing a great number of perforations into engagement with thesprocket teeth which greatly attributes to preserving the edges of theperforations of the film. The groove I I in the cam disk is shaped witha circular portion having a flattening and is adapted to impart to thesprocket, which is nevertheless continuously rotated by the pinion I5, asudden upwards movement during the image exposure which will cause thesprocket to perform. a short backwards rolling on the film and a shortstopping of the same in the projection aperture. The sprocket isarranged near the lower end of the gate I9 provided with the projectionaperture 20. A guiding roller 2| disposed above the sprocket assurestogether with a pressure roller 22 in contact with the sprocket the goodcontact between. sprocket and film 23 which is introduced into the gate.

The film delivered from the gate I9 passes from underneath to alengthened portion of the sprocket I8 and is held in good contact withthis sprocket by a roller 24 mounted on the same axis with the roller22. The film passes then over the roller 24 to the take-up roller 25which is mounted on a shaft 26 journalled in the standard and carryingon the other side of this standard a chain pinion 2! moved by thesprocket pinion I I. The film supply roller 28 is mounted to a shaft 29which crosses the standard 8 and carries on the other side of thisstandard a chain pinion 3o actuated by the chain drive of the film.

The operation of the feeding device is as follows:

When the device is working, the shaft I turns as indicated by the arrowin Fig. 2 and drives by means of the worm 6, the Wheels 9 and pinion I5and the wheel I4 with the sprocket drum I8 which during its rotation issubmitted to an cscillating movement corresponding to the form of grooveii in the cam disk 5 which oscillates the arm l3 supporting said wheelM. This movement results in a back rolling of the drum on the film andprovokes at a given moment a rapid sinking of the arm !3 into its lowestposition. During this sinking when the roller [6 has passed the righthand portion of the groove and has reached the radius A of the disk(Fig. 2), the former picture will be withdrawn from the aperture 20 andreplaced by a new one. The roller I6 travels now on the curved positionof the groove and causes the arm I3 to rise. During this passage inorder to maintain the film stationary before the aperture, the sprocketl8 continuing turning will travel upwards on the film until the rolleris again at the beginning of the straight/portion of the groove wherethe withdrawal of the picture takes place. During this sudden downwardmovement of the sprocket the film is wrapped round nearly half itscircumference and will therefore be engaged by a great number of teethquite differently from the film contact in well known apparatus wherethe film is never engaged by more than one or two teeth.

The movement of the sprocket is more exactly as follows:

We suppose that the roller i6 is at the part of the groove 1'? whichcorresponds to the radius A in the Fig. 2, that is corresponding to thelowest position of the sprocket shown in Fig. 5, where the axis of thesprocket has arrived at the lowest point of its swinging movement. Thecam is designed so as to turn in the direction of the arrow in Fig. 2through an angle of of the whole circumference that is 300 from radius Ato radius B corresponding to the uppermost position of the sprocket, thewheel It will be turned through an angle depending on the ratio of thegearing. The ratio is such that if the circumference of the sprocket hasa length equal to twelve pictures the angle is 25. During this turn thegroove I! of the cam displaces the arm l3 through an angle a, see Fig. 6such that during which movement the sprocket rolls backwards on the filmwithout any sliding, and the film remains stationary in the positionwhere the picture is projected. The cam continues turning and travelsthe last turn from B to A. The form of the groove is such, that itcauses a rapid sinking of the arm through the angle a, see Fig. '7. Thecombined movement of this angular displacing with the consequentrotation of the wheel 14 upon the pinion 15 effects a sudden advancingof the film by the height of a picture. The same movements will berepeated at each turn of the shaft I.

The mechanism as represented is incontestably that which gives the bestresults for preserving the film. Only continuous feed mechanism couldgive somewhat better results.

This device is a synthesis of the different systems in use. Indeed itcomprises a maltese cross but having a continuous and not a jerkingmovement. It works on the film by pressure and takes it along byadhesion. The adjusting of the film is more exact than that by means ofsprockets alone and the film is engaged by a plurality of teeth.

What I claim is:

In an intermittent feeding device in cinematograph apparatus and incombination, a motor shaft, a driving shaft and a friction gear asdriving means between the two, a worm formed on said driving shaft and ashutter and a grooved cam disk fast thereto, a pivot pin fast to theframe, a sleeve fitted on the pin and a worm wheel fast to the sleeveand meshing with said worm, a pinion integral with this worm wheel and arocking arm pivotally held on said pivot pin and having a roller at itsend guided by said grooved cam disk, a journalled shaft carried by saidarm, a spur wheel meshing with said pinion and mounted on saidjournalled shaft and a sprocket, one half side of which being enlaced bythe intake film formed into a loopand the other half side enlaced by thepay out film, the shape of the groove in the cam disk being such thatwhile the rotating movement of the sprocket remains continuous thislatter receives at each turn a sudden upwards movement to produce thestoppage of the exposed picture by a backwards rolling on the film, twopressure rollers mounted upon the standard, one roller to press the takein film against the sprocket and the other arranged so as to have thewhole half circumference of said half sprocket side enlaced by thepay-out film, a sprocket pinion provided at the end of said sleeve, aroller for the pay-out film, a roller for the take-up film and a chaindrive adapted to transmit motion from said sprocket pinion to the twofilm rollers.

JEAN LAAGER.

